Improvement in burglar-alarms



T. D. LOGKWOOD.

` Burglar-Alarm.

Patented July/15,1879.`

l wie "s" Zum/m N;PEFF.RS, PHOTO-LITHOGHAFHER. WASHINGTDN, D. c.

UNITED STATES PATENT Our-rou THOMAS LOCKWOOD, OF ELIZABETH, NEW JERSEY.

IMPROVEMENT IN BURGLAR-ALARMS.

Specification forming part of Letters Patent No. 217,543, dated July 15, 1879; application. filed April 24, 1879.

To all lwhom it may concern.'

Be it known that I, THOMAS D. LocKWooD, of Elizabeth, in the county of Union and State of- New Jersey, have invented an Improvement in Burglar-Alarms, of which the following is a specification.

Burglanalarms are so seldom called into use that .in many instances they do not properly operate, or else changes in the temperature or the condition of the battery cause such alarms to give a false signal, greatly to the annoyance of all concerned.` 'This is particularly the case where vaults or safes are guarded by electric connections to a police-station or to any other place for alarm.

I provide a means for equalizing the electric action upon the alarm at any time, and for intensifying the electric action in case of any disturbance or breaking of the circuit at the safe or place that is guarded. Thereby my burglar-alarm is very delicately adj usted; but it is not liable to give any alarm in consequence of change in the condition of the battery o r of the atmosphere.

I have represented in the drawing a diagrain of my improved burglar-alarm circuitconnections.

a is the main battery. b is the safe, vault, or other device that is to be protected; and at this vault or safe there is to be any desired or ordinary circuit breaking device, the same operating when the alarm is to be given.

The wire c leads from the battery a through the switch-board d to the branch wires 2 and 3. in which are placed the rheostats r r1. Thence the line passes by 4, 5, and 6 to the safe to be guarded, thence through rheostat r2 and wire.7 to ground g.

The alarm-instrument is to be of any desired character; but it is to be placed in the bridge-wire, for reasons herein set forth.

I have shown a polarized relay, f, working a local circuit-alarm having a call-bell, h, battery t', and local circuit, through the armature lof the polarized relay to the contact-points 9 and 10.

The armature is kept central and the local circuit broken between l and 9 and l() 5 but if the balance of the electric forces acting in the and 14; but by placing the pin from 12 into' 13 and removing the pin from 14 altogether, the branch 2 3 will be thrown out of circuit, and the alarm atA the safe sounded to see that all is in order.

The rheostat r2 at the safe does not require to be adj ustedfalience all the adjustment required is at the police or central station. This rheostat r brings a resistance into the line, and renders the adjustment of the line` and safe connections more delicate, so that si g nals will be given at the central station if the line or safe connection is disturbed at any point.

When the pin at the switch board s is c anged from 16 into 17, the current will actA uate the electro-magnetic alarm t, and the disturbance at the central station, caused by moving the pin at vs at a given time of day, may be understood beforehand to indicate that the current is to be put on in its strength by placing the pin-switch in the hole 13 to test the line and see that it is in order. At the safe the pin, except when the alarm is set, will usually be in 18, connecting directly to the ground.

It will be apparent that the battery being connected to the branch 2 3, and the alarnr instrument being in the bridge, the alarm is not operated by any rise or fall of battery power, or by changes in the atmospheric con dition; but so soon as the line is disturbed at the safe or elsewhere the balance in the bridge is destroyed and the alarm given.V

I claim as my invention- 1. The combination, with a burglaralarm, of a branch, artificial line, main line, and bridge circuits, and an alarm -instrument placed in the bridge, substantially as and for the purposes set forth.

2. The polarized relay in the bridge-Wire and a burglar-alarm, in combination with lhe rheo- Signed by me this 21st day 0f April, A. D.

stats 1*' rl in the branch, the 'rheostat r3, and 1879.

battery ab the police or central sta-tion, and a line extending to the circuit-breaker at the safeor other article to be guarded, and the switches or switch-boards, substantially as set fort-h, for testing the burglar-alarm and line, substantially as set forth.

THOS. D. LOGKWOOD.

Witnesses:

GEO. T. PINQKNEY, WILLIAM G. MOTT. 

